Contents

Abstract

### Background

Soil-transmitted helminths, a class of parasitic intestinal worms, are
pervasive in many low-income settings. Infection among children can lead
to poor nutritional outcomes, anaemia, and reduced cognition. Mass
treatment, typically administered through schools, with yearly or
biannual drugs is inexpensive and can reduce worm burden, but
reinfection can occur rapidly. Access to and use of sanitation
facilities and proper hygiene can reduce infection, but rigorous data
are scarce. Among school-age children, infection can occur at home or at
school, but little is known about the relative importance of WASH in
transmission in these two settings.

### Methods

We explored the relationships between school and household water,
sanitation, and hygiene conditions and behaviours during the baseline of
a large-scale mass drug administration programme in Kenya. We assessed
several WASH measures to quantify the exposure of school children, and
developed theory and empirically based parsimonious models.

### Results

Results suggest mixed impacts of household and school WASH on prevalence
and intensity of infection. WASH risk factors differed across individual
worm species, which is expected given the different mechanisms of
infection.

### Conclusions

No trend of the relative importance of school versus household-level
WASH emerged, though some factors, like water supply were more strongly
related to lower infection, which suggests it is important in supporting
other school practices, such as hand-washing and keeping school toilets
clean.